Exercise bicycle



FIG. 1 is a side perspective view of an exercise bicycle showing my new design;

FIG. 2 is a left side perspective view thereof;

FIG. 3 is a right side perspective view thereof;

FIG. 4 is a front perspective view thereof;

FIG. 5 is a rear perspective view thereof;

FIG. 6 is a top perspective view thereof; and

FIG. 7 is a bottom perspective view thereof. 

The ornamental design for an exercise bicycle, as shown. 